1
Seeger Jr Richard E, Lynn William J: Keyboard switch assembly with improved operator and contact structure. Chomerics, March 20, 1973: US3721778 (31 worldwide citation)

An encoded keyboard device which includes a plurality of layers of insulator material, at least two of which have patterns of electrically conductive material supported thereby, a plurality of holes extending through one of said layers and positioned with respect to said conductive patterns so that ...


2
Seeger Jr Richard E, Coulter John G: Multi-output level keyboard switch assembly with improved operator and contact structure. Chomerics, Dike Bronstein Roberts & Cushman, January 29, 1974: US3789167 (22 worldwide citation)

A structure which includes a circuit board having a conductive pattern thereon and supporting a resilient conductive layer by way of an insulator layer having a plurality of windows therethrough in alignment with portions of the conductive pattern, the resilient layer divided into at least two secti ...